By iontophoresis application of Gal, the effects of Gal on basic response properties such as rate-intensity functions (RIFs), frequency tuning curves (FTCs), discharge pattern of inferior collicular neurons of mouse were investigated. A total of 96 neurons were attained with single and multiunit recording method from mouse (Mus musculus, Km) IC.

In order to study the effect of weak noise on the sound signal extraction of mouse (Mus musculus Km) inferior collicular (IC) neurons from environments,we examined the changes in frequency tuning curves (FTCs) of 32 neurons induced by a weak noise relative to 5 dB below minimum threshold of tone (reMT-5 dB) under free field stimulation conditions.

6) The mutual facilitation between paired neurons not only increased discharge rate, but also widened the frequency tuning, i.e., increased response frequency.

In order to study the effect of weak noise on the sound signal extraction of mouse (Mus musculus Km) inferior collicular (IC) neurons from environment, we examined the change in frequency tuning of neuron induced by a weak noise relative to 5 dB below minimum threshold (reMT-5 dB) of tone. 12 healthy adult mice (20-25 g, b. wt.) were used for this study.

Neither such shift of spatial frequency tuningcurves of the P-VEP in adult cats, nor such functional competition between the twoeye in P-ERG responses during early development of kittens of monocular deprivationand reverse suture was found.

The units tuned to exposing frequency in animals exposed at the first and third postnatal week showed stronger clustering compared to the control and those exposed at the fifth postnatal week. The tonotopic organizations and Q10-dB values of the units were also abnormal.

The intensity-rates functions,intensity-latency functions and frequency-turning curves were recor(ded) by extracellular electrophysiological recording techniques.

Retinal ganglion cells of type X show, for scotopic levels of luminance, a flattening of their spatial frequency tuning curves in the low spatial frequency range.

Spatial response profiles to stationary and moving stimuli and spatial frequency tuning curves to drifting sinusoidal gratings were recorded from a series of cells in the simple family.

On the assumption that cells in the simple family operate linearly, spatial response profiles recorded experimentally were compared with those predicted by inverse Fourier transformation of the spatial frequency tuning curves.

Conversely, the spatial frequency tuning curves recorded experimentally were compared with those predicted from the response profiles to moving and stationary stimuli.

The discharge variance was on average 1.7 times the mean rate for data obtained from measurements of the neurones' spatial frequency tuning curves, and 1.48 times the mean for data from the response-contrast determination.

126 lateral geniculate neurones were examined on unanaesthetized immobili-zed cats.The temporal frequency tuning curves of single neurones were measuredby stimulating the cat's eye with a sinusoidally modulated light spot,generated ona CRT and presented to each neurone's receptive field center or its surround.Theaverage discharging rate was used as an index to judge the sensitivity to different mo-dulating frequencies.By comparing the mean impulse rates responding to modula-ted light stimulations(modulated discharge...

126 lateral geniculate neurones were examined on unanaesthetized immobili-zed cats.The temporal frequency tuning curves of single neurones were measuredby stimulating the cat's eye with a sinusoidally modulated light spot,generated ona CRT and presented to each neurone's receptive field center or its surround.Theaverage discharging rate was used as an index to judge the sensitivity to different mo-dulating frequencies.By comparing the mean impulse rates responding to modula-ted light stimulations(modulated discharge rate)with those responding to unmodulatedlight(unmodulated discharge rate),two opposite effects were observed.The majorityof the cells(93.7)% showed modulation-excitatory curves in which the modulateddischarge rates were higher than the unmodulated ones.A minority of the cells(6.3%)showed modulation-inhibitory curves in which the modulated dischargerates were lower than the unmodulated ones.The modulation-excitatory curvescould further be grouped into two subtypes,the“band-pass filters”and the“low-pass filters”.Similarly,the modulation-inhibitory curves could also be dividedinto two subtypes,the“band-rejection filters”and the“low-rejection filters”.Onboth sides of the temporal frequency tuning curve subsidiary sidebands oppositein direction to the main part of the curves could often be seen,i.e.inhibitorysidebands flanking the modunation-excitatory tuning curve and excitatorysidebands flanking the modulation-inhibitory tuning curve.Most of the tuningcurves have only one peak.of the 110 curves measured the peak loci show anormal distribution which centered at 7 Hz.The tuning curves due to stimulationof different locations of the periphery were almost the same.But the tuningproperties of the receptive field centers were different from those of the periphe-ries either in shape or in band-width.

The frequency tuning curves of 24 sustained and 28 transient geniculate neu-rones were determined.All the sustained cells presented“band-pass”tuning pro-perties,while the majority(64.3%)of the transient cells showed“low-pass”cha-racteristics.However,some of the transient cells(21.4%)also showed typical“band-pass”tuning curves and still some(14.3 %)showed tuning properties somewhat bet-ween the mentioned typical types.The coming into being of the various shapesof the tuning curves in relation to the two types...

The frequency tuning curves of 24 sustained and 28 transient geniculate neu-rones were determined.All the sustained cells presented“band-pass”tuning pro-perties,while the majority(64.3%)of the transient cells showed“low-pass”cha-racteristics.However,some of the transient cells(21.4%)also showed typical“band-pass”tuning curves and still some(14.3 %)showed tuning properties somewhat bet-ween the mentioned typical types.The coming into being of the various shapesof the tuning curves in relation to the two types of geniculate cells was discussed.

Temporal tuning curves of 19 transient and 22 sustained geniculate neuronesof unanaesthetized immobilized cat were determined by using a sinusoidally modula-ted light spot of 0.3°projected to the receptive field center.The sensitivity peakand the degree of modulated change of discharge rate of the tuning curves of tran-sient cells remain practically unaltered with change of mean luminance,reflectinga property of such cells that their average discharge rate is insensitive to the levelof steady illumination.In...

Temporal tuning curves of 19 transient and 22 sustained geniculate neuronesof unanaesthetized immobilized cat were determined by using a sinusoidally modula-ted light spot of 0.3°projected to the receptive field center.The sensitivity peakand the degree of modulated change of discharge rate of the tuning curves of tran-sient cells remain practically unaltered with change of mean luminance,reflectinga property of such cells that their average discharge rate is insensitive to the levelof steady illumination.In contrast,the discharge rate of sustained cell due tomodulation is more or less proportional to mean discharge rate of such cells tounmodulated light of different luminances,while the sensitivity peak remainsunchanged.Of the 6 hi-peaked temporal tuning curves,decrease of light by 1-2log units leads 4 of them to a disappearance of the high frequency peak.Possiblemechanism for the coming into being of the bi-peaked tuning curves was discussed.